个人技术分享

chapter14.1.pl

#!/usr/bin/perl -w
chdir "/" or die "can't chdir to / : $!";
system "ls -l";

chapter14.2.pl

#!/usr/bin/perl -w
if(chdir "/ussss") {
  if(!open DIR_LOG,"+>>ls.out") {
    die "Cannot create log file:ls.out : $!";
  }
  else {
    my $dir_massage = `ls -l`;
    print DIR_LOG $dir_massage;
    close DIR_LOG;
  }
}
else {
  if(!open ERROR_LOG,"+>>ls.err") {
    die "Cannot create log file:ls.err : $!";
  }
  else {
    print ERROR_LOG $!;
    close ERROR_LOG;
  }
} 

chapter14.3.pl

#!/usr/bin/perl -w
my $data_massage = `date`;
print "$data_massage\n";
if($ex_vld = index($data_massage,"Sat") != -1) {
  print "go paly\n";
}
elsif ($ex_vld = index($data_massage,"Sun") != -1) {
  print "go paly\n";
}
else {
  print "go to work\n";
}